August 12, 2025, 4:57 pm | Read time: 5 minutes
According to a new study, fox tapeworm infections are on the rise in Europe. Specifically, it concerns a dangerous infection that can go unnoticed for years and, if untreated, is almost always fatal for humans. Although the numbers are still relatively low, the trend is worrying. But what does this mean specifically for dogs?
Fox Tapeworm Infection Can Be Fatal
New data shows: The number of fox tapeworm infections in humans is increasing—especially in Germany, France, Austria, and Switzerland.1 The fox tapeworm—medically known as Echinococcus multilocularis—is a dangerous parasite that, while rare, can be very threatening to humans.
The infection occurs through the excretions of infected foxes. Tiny eggs of the fox tapeworm, barely visible to the naked eye, enter the environment through their feces—on grass, soil, mushrooms, or berries. Those who eat unwashed forest fruits or touch contaminated surfaces and then touch their mouth can ingest the eggs. These enter the body, preferably settle in the liver, and develop tumor-like larval tissue that can spread to other organs.
“Symptoms Appear Only After Ten to Fifteen Years”
“Humans usually become infected unnoticed,” explains veterinarian Dr. Vanessa Herder in an interview with PETBOOK. “Symptoms appear only after ten to fifteen years—by then, the disease is often already advanced and can be fatal if untreated.”
Unlike many other parasites, it does not grow in a capsule but infiltrates the tissue—similar to a malignant tumor. “This makes surgery often difficult,” says Dr. Herder. Unfortunately, the disease is often only recognized when the damage is already significant. It cannot be transmitted from person to person.
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Dogs Can Also Become Infected
But why are fox tapeworm cases increasing in Europe right now? The scientists of the study assume there is a connection with the growing fox population and closer contact between wildlife, pets, and humans, such as during outings in nature. Additionally, foxes are increasingly settling in residential areas and cities and spreading further. “Another reason was the vaccination of foxes against rabies,” says Dr. Herder. Since fewer foxes die from rabies, more can transmit the tapeworm.
Dogs can also become infected. Although studies show that less than one percent of tested dogs in Germany are affected, the actual number is likely higher, according to Dr. Vanessa Herder. Hunting dogs—those with direct contact with wildlife like foxes—are particularly affected. “City dogs without wildlife contact have a very low risk,” she explains.
Infected Dogs Can Transmit the Pathogen to Humans
The infection in dogs is mostly inconspicuous. They usually show no symptoms—many owners do not even notice that their pet is infected. In very rare cases, such as when dogs themselves act as intermediate hosts and the larval stages develop in the body, it can lead to organ changes, for example in the liver. “But this is extremely rare,” says the veterinarian. In practice, the infection usually remains symptomless and is only detected through targeted fecal examinations or serological tests at the vet.
What many do not know: Infected dogs can transmit the pathogen back to humans—through feces or even dirty fur. This is particularly risky if the dog rolls around in forest areas where foxes are also present.
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Washing Hands Can Save Lives
It is all the more important for pet owners to take proper precautions. Therefore, Dr. Herder has clear recommendations: “Hygiene, hygiene, hygiene.” Regular deworming is mandatory—especially for dogs that are often outdoors. After a walk in the woods, both the dog and accessories like leashes or toys should be thoroughly cleaned.
And of course, don’t forget to wash your hands—especially after contact with the animal or after walking the dog. Owners should also ensure that their pets do not catch mice or hunt other wildlife.
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But what exactly do the numbers mean, and in which regions is there a particularly high risk of infection? According to the current study, the Alpine region and the Baltics are considered risk areas for the fox tapeworm. Between 1997 and 2023, 4,207 cases of so-called alveolar echinococcosis were documented across Europe.
In These Regions, the Fox Tapeworm Risk Is Particularly High
According to the Federal Institute for Risk Assessment (BfR), 26 to 32 percent of foxes living in Germany carry the pathogen. However, this distribution is not the same everywhere: There are so-called high-endemic areas within Germany, particularly in Bavaria and Baden-Württemberg. These include, for example, the Swabian Jura, the Allgäu, and Upper Swabia. According to the study, capturing the numbers is not easy, as in many countries, fox tapeworm cases are not recognized or reported.2
Since there is no central recording for infected pets, many cases go unnoticed here as well. Experts therefore assume that the number of unreported cases is significantly higher than the official figures suggest. Especially in regions with high fox density and more frequent wildlife contact, the risk can be underestimated accordingly.